Recommended guidelines for hormone replacement therapy (HRT) sure have come a long way since the abrupt end of the Women s Health Initiative (WHI) trial in 2002. At that time, researchers became concerned about the increased risk of blood clots and stroke associated with the treatment. Following this trial, HRT use declined precipitously, as women and their doctors became reluctant to use this therapy. However, the scientific community has slowly begun to reassess HRT, as researchers find that the risks don t merit the level of concern they were once thought to, and the benefits often outweigh the risks. In fact, just last week, the North American Menopause Society announced a more flexible approach to HRT and now a study in The Lancet Oncology shows that estrogen-only HRT may actually lower some women s risk of breast cancer.
In this most recent study, a researcher from the Fred Hutchinson Cancer Research Center in Seattle and colleagues analyzed data on more than 7,500 postmenopausal women between the ages of 50 and 79 who d had hysterectomies, all of whom had participated in the WHI trial. (Their participation was significant, since only women who have had hysterectomies can get estrogen-only therapy; the therapy increases the risk of uterine cancer unless progesterone is also used.) These women had taken either estrogen-only therapy or a placebo for a total of around six years. Nearly five years after therapy had ceased, researchers found that women taking estrogen-only HRT were 23 percent less likely to develop breast cancer than those in the placebo group. Furthermore, even when the women in the estrogen group did develop breast cancer, they were 63 percent less likely to die from the disease.
This is an intriguing result, comments ACSH s Dr. Gilbert Ross. We tend to think that estrogen fuels breast cancer. So it s surprising to find that estrogen-only HRT can actually reduce breast cancer risk.
ACSH s Dr Josh Bloom agrees. He points out that, since estrogen blockers, including tamoxifen and aromatase inhibitors, have been widely used to prevent recurring breast cancer, there are obviously complexities about the biochemistry of estrogens and cancer that are not understood.
As the lead study author states, These latest results should provide reassurance about breast safety of [estrogen] use for durations of about 5 years for women with a hysterectomy seeking relief from postmenopausal symptoms. ACSH s Dr. Elizabeth Whelan agrees that this study will add to the evidence that HRT can have some important and significant benefits for women, countering fears that many women have had since concerns about the 2002 WHI trial emerged.